A Panoply of Rainy Days
by Moonlight M3lody
Summary: Some people, upon a chance meeting for the first time, would inevitably spend their whole lives together. A slow burn, jargon-filled study about a language for two.


**A Panoply of Rainy Days**

* * *

_"A set is a Many that allows itself to be thought of as a One."_  
_-Georg Cantor_

* * *

Some people, upon a chance meeting for the first time, would inevitably spend their whole lives together. They had forgotten how days were before that and a future devoid of that person, while possible, was unthinkable.

* * *

**1\. Axiom**  
Sou Touma had retreated to the warmth of his study long before the rain started to hit the pavement outside. The padded walls, lined up with bookshelves from floor to ceiling, provided the much needed insulation against the harsh seasonal weather. Every now and then, swishing wind and crackled branches joined what little could be heard from the downpour.

It's only 8 PM, a perfect time to wind down before another day of busy labour at school. Mizuhara wanted him to come early to help with this stage play their class would be performing around the corner, though he wasn't sure the girl herself could make it on time. He poured himself hot chocolate and cracked open a book, ready to surrender the world for some peaceful reverie with the written words. Logged out of his computer and having his phone turned off, he was not expecting any particular human interaction for a little while, so it took him some time to recognize the rhythmic sound coming from the outside was not footsteps from any random passers-by but rather determined knocks to his door.

The wind came in full force once he opened the door shielding his space to the outside world, muffling his voice down so much he'd had to strain to be heard. The woman before him was trying hard to cling on her umbrella, her coat flailing violently. It was no longer a cozy rain, it was almost a storm.

"Eva?"

...

A few minutes later, once everything was sufficiently dried and warmed, with a nice, steamy cup of beverage for his guest to go along, Sou invited her to explain how she ended up on his front porch at such hour.

"I wasn't aware you're in Japan. Loki didn't say anything."  
Eva took a sip of her drink, savoring the decadence after all the humdrum aside. "I was here on my own. An IT company consulted my lab for their AI literacy training program, so I came to take some preliminary survey. As it was, I forgot to check the weather. I think I have underestimated how bad it could be around here."

Sou raised his eyebrows, glancing to the clock. She was quite drenched when he found her, though not wet enough to be out for long.  
"The meeting took you past dinnertime?"  
"Ah, not really. I was planning to stop by, so I took a train here after dinner. Though... judging from the current situation, I may have to impose on you a little longer than I planned."  
"Given that Loki didn't even know you're coming, I guess you have some reason for your visit?"  
"You're sharp as always," she smiled. "Say, it's been a long time since we had time to talk, so I thought I'd want to clear up a few things with you."

...

The moment Eva mentioned something she didn't dare to talk in front of Loki, Sou immediately knew what it was about. There were very little secrecy between the two of them, and even little anything that would be related to him in any way. He had chosen to put it behind, for the matter was already resolved in a manner he was personally satisfied with, but it occurred to him that he had never given the chance for Eva to have her closure. So he pulled a seat closer, signifying he was ready to listen, then let her talk.

Eva Sukta never really understood Sou Touma. They were friends because Sou and Loki clicked and Loki took him under his wing right away. For most of their time in MIT, Eva envied Sou. It took a genius to understand a genius, but Eva would like to believe her effort had something to show. Sou's presence had lightened and softened Loki the way she couldn't. While she was thankful because Sou had made Loki happier than he ever was, Sou was still not someone Eva would normally become friends with. He was an enigmatic person. While he was generally polite to everybody, there was something Eva couldn't quite put a finger on. Whether it was uncanny intuition or remarkable perception, it unnerved her. She voiced this once to Loki; he laughed at her because Eva lacked the depth to fathom someone of his caliber.

At the end of her internal discord, however, after she tore his thesis and realized he had known what she had done, she slowly learnt what felt wrong: it was unnatural for someone to have that much light within them. She'd been in the academe far too long to know that you either become corrupted or depressed at some point, but nothing ever seemed to faze Sou Touma. Not even her action incited his anger. He treated everything and everyone with indifference, with the same detachment as if he was living somewhere faraway.

Sou waited until Eva was done, watching steam rose from the kettle. The end of his glasses were fogged. He took them off.  
"I cannot find it in me to be angry with you, Eva," he started. "Because deep down, at that time, I was actually relieved."  
Eva scanned his eyes, suddenly looking older than they should. For the first time, he looked genuinely sad. She braced herself to hear what more to come. She had promised herself to try her best this time.  
"If anything, I was angry at myself to have handled the aftermath so poorly. I should have straightened the facts before people started talking."

He turned to face her. "Don't get me wrong, I truly enjoyed my time there and regret nothing of it, but at the end of our undergraduate studies, I was beginning to lose my sight on what I was seeking. I went into graduate classes right after because I convinced myself the doubt would disappear on its own. For a long time I struggled with the questions. Why me? Why do this?"

As a student guide during her years in MIT, she knew better than anyone the kind of madness plaguing those with the brightest minds. Impostor syndrome, crippling anxiety, paranoia, the list could go on and on. It was prevalent, and she could show the suicide statistics to back it up. It dawned on her that she might have always been wrong about him. The darkness was there after all. He was just too adept in hiding it, or perhaps she simply refused to acknowledge. Everything she didn't see because she was so concerned about Loki now came to surface with utmost clarity.

"I had never resisted the allure of mathematics. It was a wonder, a pursuit of endless curiosity. But at the same time, I began to see how people drowned themselves in the pursuit. Cantor believed that the essence of mathematics lies in the freedom, but instead these people became slave to the equations. I was looking for something undefined, and the feeling nagged on me immensely. Perhaps I was afraid I would be one of them and wanted something to keep me tethered in this world."

He didn't specify a name, but Eva couldn't help but be reminded of Professor Refla. The boys had always thought of him highly, and Loki had returned from that trip looking particularly sullen. Maybe it had affected Sou the same way, or maybe it was someone else she did not know. Sometime Eva wondered whether math was truly his calling or a path he followed along simply because it came to him easily. She didn't remember when she decided she liked computer science. It certainly wasn't at fourteen, but once her parents discovered her affinity to STEM, she couldn't remember she had any room to consider anything else. Touma had come to MIT at ten, finished his undergraduate before he turned fourteen, and on his way to get his master's at fifteen. Before he met Loki, was he just as lonely?

"Eventually, the emptiness grew. I didn't think I could continue my research with that kind of hesitation. However, once my thesis was submitted and approved, I would have been inducted into the lab. I couldn't stop working on it as it would bring trouble to my advisor. That's why when I found out someone destroyed it, I was unable to be angry. I was glad."

She wasn't sure what to make of this revelation.

"So why Japan?" She tried to keep her voice steady, but it was hard to stop trembling.  
"Are you familiar with Morris Kline, Eva?" He smiled.  
Eva nodded, though not sure how it was relevant to her question. "Loki looks up to his works."  
Sou rose from his seat, locating a well-worn tome from the shelves nearest to his desk. He handed her the book. It automatically opened to a page he must have opened many times for the spine to be bent in that particular direction. A particularly long passage had been highlighted.  
"I read that in college, and it resonated with me during those times."  
Eva bent down to read:

_...mathematics per se does not deal with human beings and the complex problems that dealing with human beings pose. As Bertrand Russell said, "Remote from human passions, remote even from the pitiful facts of nature, the generations have created an ordered cosmos, where pure thought can dwell as in its natural home and where one, at least, of our nobler impulses can escape from the dreary exile of the actual world." Hence mathematics is likely to attract those who do not feel competent to deal with people, those who shy away from the problems of the world and even consciously recognize their inability to deal with such problems. Mathematics can be a refuge."He also said in his autobiography that abstract thinking destroys our humanity and draws us into ourselves, and he confessed that he was drawn into mathematics because it is not human..._

"...so, this?"

"Bear in mind that he was talking within the context of American math education, but it intrigued me nonetheless. I had lived in math for so long, I wondered if I should go out and try something else."

He closed his eyes. "After that incident, I received a postcard from my cousin. He had fled his home in search of his own place in the world. I thought that perhaps what I needed too, to see the world with my own eyes. People keep talking about their high school days, so I figured I could give it a try. Although I grew up in America, I still have my Japanese nationality. It wouldn't hurt to live here for a while."

"I suppose you've found your answer, then? You're becoming a lot more eloquent and conversant, if I may say."

Eva couldn't imagine the Touma she knew before would open up like this. They had talked more in an hour than the five years of college combined, unless one would count everything academic. Unfortunately, debating calculus wouldn't get you too far in knowing someone as a friend.

"Is that evident?"  
She offered him a warm smile which he replied in kind.  
"Yes."  
"At first, I was set on walking down the same path. When I first came to Japan, I told myself that I had everything planned. That I wanted to observe how real life was. But in reality, Loki wasn't wrong when he said I was running away, and as such nothing changed. I paid attention to the classes, but talked to no one. I spent my time reading on the roof. I did not try to socialize. Whether it was in Japan or in America, I passed high school the way I always did."

"Then... what changed?"

"I met a certain someone. You probably can guess."

"I... yeah."

"For the first time in my life, I felt connected to the world around me. Slowly, I felt less like an outsider, and more like being part of something. Ever since I came here, I got to see many things I would never have otherwise. I participated in the school festival, I took up oil painting. I met wildly different people, but more importantly I found something without name or form. The cherry blossoms were blooming and it struck me at once."

When Loki and Sou exchanged arguments in a particular topic, it was a sight to behold. People, particularly young assistant professors, used to come and take note at the vigorous back-and-forth, usually accompanied with several boards full of equations. Eva was lucky to always had the front seat to those discourses. This Sou was talking with the same fondness to the subject.

"She would come and be angry at me for all the 'unnecessary thinking'. She's a very simple person, but she'd solved such a complex problem. Don't you think she's very interesting, Eva?"

"I see what you mean," she agreed, remembering the girl who had pieced the truth on her own and chased them all the way to the airport. There was something in that honest tenacity she rarely saw in her usual circle. That must be what Sou was thinking about too, because his next words were, "She sees the world differently, and I... want to see a glimpse of that."

He stopped, turning around to face her. "Do you think it's weird?"

Eva shook her head, trying to look sincere. "No, forgive me for saying this, but... I suppose you're more human than I previously thought, and I'm glad for that." She owed the apology for a long while. It felt good to be able to finally say it.

"Only machines are completely controlled by logic.". Eva wasn't sure what prompted this particular comment, but she had a good hunch it was some kind of inside joke for him, whose lips had subtly upturned as he said that.

Choking on her own impudence, she braved herself to ask the most important question. She needed this. She had come all the way here for a confirmation.

"Are you happy, Touma?"

"I am."

He glanced to the side of his living room where crates of props had taken residence. Kana had been ecstatic with the upcoming play, the last of such events the seniors were allowed to participate in. If he had to evacuate a shelf in anticipation to unforeseen accident, then so be it. He wasn't running out of space for the moment (though it had to be reassessed when the shipment for the books he ordered yesterday arrived).

Again, Eva didn't know what amused him so, but the answer itself lifted tons of burden off her shoulders. While he blamed himself for the incident, Eva had caused something unforgivable in any other circumstances. With this, she could finally move on and perhaps learning to forgive herself as well.

Suddenly addressing him as a friend no longer felt like shameless guilt.

"May I know what you're planning to do after this?"  
"I'm going to return to MIT for my graduate studies."  
He would have to repeat the entire year because his thesis was already voided, provided the college would admit him again, but it was hardly a setback.  
She looked at him quizzically.  
"I'm no longer afraid."  
"Of being absorbed into your own works?"  
"We mathematicians are obsessed with boundary conditions. I promised her I wouldn't go to the other side."  
"She is, then, your boundary condition?"  
"You can say so."  
"Loki would be delighted."  
"I'm looking forward to hanging out with the two of you again."

Their cups had been empty for a while now, the kettle cold to the touch. Sou made a move to refill it, but Eva signaled that she would be leaving.

"I'm sorry to have taken up your time with this kind of talk."  
"Don't be. I'm glad to have this cleared up, and... I thought that perhaps you would be able to understand this more than Loki would."  
"I suppose I am, if you put it like that."

Loki might be Sou's best friend, but he was fallible in thinking that everyone thought the way he did. Loki was content with Sou, but even he had failed in getting through the younger man. Eva wasn't sure anyone managed to come close before a certain young girl. Sou was right. She had managed to solve a riddle no one else could.

It took the brightest sun to clear the sky after the heaviest of rain.

* * *

The atmosphere of the room started merrily enough. Recognizing "the boy wonder" and "the genius trickster" from MIT, the group was quickly welcomed among the researchers. Not losing any chance to impress, some of them began to rattle about their recent discoveries. However, the conversation took a quick turn for the worst when Kana, unaware of the minefield around her, waved cheerfully as she commented, "But what does this all have to do with the real world?" to the crowd of pure mathematicians.

As if a bucket of ice had fallen to drop the room's temperature near subzero, everyone suddenly froze in place. Loki and Sou facepalmed, Eva dropped her binders, the applied mathematicians in attendance snickered, and the whole faculty was flabbergasted. Before they knew it, they were ushered out of the conference hall to the lobby by a savvy junior researcher in attempt of incident mitigation.

When the crew could find their words again, Kana was waiting expectantly for any kind of explanation because that was just plain _rude_.

"You just have to say that!" grumbled Sou. For all the days she missed her tact, it just had to be _today_.

"Well, you didn't warn me! How do I know speaking about it is forbidden?" she balked, just angrily enough to silence the other two people.

Sou massaged his temples. Maybe it was partly his fault for not anticipating this outcome. "In any case, just make sure you don't bring up anything remotely close to 'real world application' to the purist researchers."

Eva, looking back and forth between the bickering pair, tried to console Kana who was still fuming. "Maybe it's better for us to split in two? She can wait until we're done with the conferences. I don't think Kana would enjoy them droning on and on either."

"Do you really have to attend it all day?"

Eva bit her lip, glancing towards the hall. "I have an appointment with one of the lecturers, so I will have to stay."

As much as he would like to attend the lectures and avoiding to point out _he_ was the working mathematician out of them four, Loki decided it was best to leave Sou there to solve the case. The proceeding would be published later anyway, waiting for him in his lab. He gave Kana a pat on the shoulder. "I know a good cafe nearby. Why don't we hang out a bit till they return? My treat."

Kana decided she would appreciate some time away from these _clearly deranged_ mathematicians.

...

Strawberry shortcake did wonder to alleviate the mood. Kana no longer like punching someone to the face by the time she finished a plate. Loki breathed a relief. He let her order some more to make sure the coast really was clear.

"So," she said between munch, "tell me what that was about. Why are they so... zealous? It's a normal thing to ask."

"Hmm," Loki sat with his arms crossed, chewing the end of a pencil as he concentrated. The question was not a foreign one, yet composing an answer never got easier. In fact, the deeper he got into his research, the harder it was to explain.

"Some people enjoy math for its own sake. They just like to do it. You don't need a reason to do something. Then there's some people who think that what you learn should have meaning." He looked around, hoping that none of the mathematicians would have their lunch break here. It was a delicate topic and he wasn't about to spark another debate.

"They don't have to be so touchy about it," she pointed out.

"Even between mathematicians there are disagreement about this. '_Mathematics derives from the study of nature and is valuable mainly because of what it returns to nature_'," he quoted, "'_The abstraction can become an end in itself, with no attempt made to apply it to significant concrete situations_.'"

When they were innocent undergraduates, it was some kind of a lighthearted sport, though there were certainly certain amount of pride involved. Students of the engineering and pure science courses would sit down together, sparring verbally as they worked on their assignments. It kept the dorm lively through the grueling academic pressure.

She stirred the glass idly, trying to rack up her brains to something she might be so overprotective of. Nothing came up. Maybe the closest would be kendo, but it didn't feel the same. "Isn't that a bit harsh? I don't really get it, but I guess it's a bit like the detectives in the police department and the investigators under the Ministry of Defense. Sometime my father complains about that."

Loki had no idea how Japanese police forces worked, so he operated in assumption Kana was better informed than he was in the matter.

"Most of the time, when you're spending too much time in one thing, you will develop some kind of internal jokes, self-deprecating thing, and it could be quite harsh to the ears of an outsider."

"Such as?"

"There was a mathematician named Richard Courant who said that rather than asking what special qualities a mathematician possess, you should ask what they lack that other human beings possess."

Kana scoffed in disbelief. No doubt the aggressiveness in that line was intentional. Either that guy was having a bad day, or he was picking a fight. "I don't know about that. You and Touma are pretty okay. Well, weird, but okay. I mean, Touma can be very insensitive, but that's just because he thinks too much." Anyone who would be so deeply interested in all those arcane equations must be a little nutty in the head. So far, she hadn't been proven wrong.

"He was kidding, of course. I don't believe Touma is that kind of person. It's true he doesn't seem to be attached to anything, but he has always been helpful. People from all the other departments used to flock on him to ask for his opinions on all sort of problems needing mathematical expertise."

The creme brulee was good, she noted as she bit into one. They should drop by this place again before returning to Japan. She scanned the dinner menu lazily, delighted that there were substantial amount of veggie-based dishes. She should order a takeaway in case the two ran late, just to make sure no one would boil a cup noodle deep into the night. Nah, that guy's diet was horrendous enough already, they should grab something better when they could eat out. She had half a mind to drag him to dinner with her family in near future if he kept it up.  
Giving the menu a last flippant look, she returned to Loki. "Isn't that just because he can't say no?"

It was amazing the girl hadn't realized how much power she dangled over him, thought Loki, something even _Alan Brad_ had figured out. The surefire way to get Sou involved in anything was to recruit Kana to their side, something he had taken advantage of himself several times (with varying amount of guilt. Hey, friends help each other, right?). "Actually, he would only take on the projects he was personally interested in. Getting a request through Touma was like a mini thesis approval. If he agreed to help, then it's worth doing."

That wasn't to say he never got strong-armed into some exceptionally troublesome matter, but Loki wasn't going to risk inciting Kana's wrath again now that they cooled it down.

For a full minute, no one said anything. It wasn't an awkward silence, but more a lazy Sunday vibe where none of them knew what exactly what they would talk about, one without a particular rush. They still had more than six hours to kill, and if the sight outside the window was any indication, the noon would be a wet one.

The cafe was cozy to her liking. Traffic was slow past midday, so they didn't feel bad taking up space for such a long time. From inside, they could watch people trudging briskly in their coats. Kana stretched her body, twisting and turning on her seat, then slumped over the table with a small purr. The gentle jazz playlist put her to a lull. When a customer to their side ordered coffee, the smell immediately filled the air. It certainly was better than having to wait in that conference hall, stuffed full with people who couldn't take a joke. She tilted her head to one side, using her left arm as a pillow. "You know Touma very well, huh, Loki?" she mumbled, a stray comment not intended to steer the conversation in any specific direction.

"Huh!?" exclaimed Loki. He shot her a baffled look. "What are you talking about? I actually envy you, you know?"

It was Kana's turn to be dumbfounded. "What? Me? What for?"

"Listen. I'm one of his oldest friends, and I thought I understood him the most, but I was wrong." When they first met each other, Loki was sure he could get Sou the way Sou got him. Unfortunately, it took four years for him to realize the error in his judgment. When Sou disappeared to Japan, Loki had spent many hours pondering where he went wrong because none of his actions made sense.

Kana shrugged. "He doesn't really tell me much. How to put it, the more I know him, the more I realize I don't know about him." Being cryptic must be an inherent feature of Sou Touma, because he did that all the time.

"You're describing an asymptote..." he mumbled. Kana twitched at the appearance of another jargon, her grip on her fork tightened. Loki winced. "Wait, let me finish. An asymptote is a line that extends infinitely towards a single point. It will keep getting closer and closer, but never quite reaching."

Huh. That was neat, thought Kana. That described what she felt perfectly. "Well, that sums it up!"

"But you aren't an asymptote, Kana. I projected myself onto him. You, on the other hand, saw through him. You probably have crossed over that line, or at the very least got the closest to him than any of us ever be."

She shrugged, nonchalant. "Yuu told me that's just because I don't let small things get to me. Sometime he tests my patience, true, but if he has anything to say, he will say it when it's relevant."

"So," he grinned. "How about the two of you?"

"What about the two of us?"

Loki scoffed. "I'm not blind."

She could be angry, or she could use the chance to sort herself in some way. Maybe Loki could be helpful. It didn't feel right to throw a fit here again, anyway, since the waiters had been so patient dealing with the noises coming from their table. The last thing she wanted was getting kicked out in this weather. All things considered, Kana decided she should try being civil.

She recounted the incident at the flower-viewing event they attended in their first year, when someone else had posed the question and pushed for an answer. As she went on, Loki felt the urge to grimace because he couldn't believe how stupid his friends had been. But of course, it was only typical.

"So his answer was whatever your answer would be?" he summed.

She nodded.

At least he got a thing or two out of this. No doubt Sou had solved his end of the equations, judging from that answer. What an ingenious design. What most other people would deem vague served a larger implication. Sou had cleverly abolished the possibility of unsymmetrical results, effectively reducing the answer sets. In a normal truth table only unanimous yes or unanimous no would remain, yet Kana had turned the tables by drawing a fuzzy middle line. Loki wouldn't be surprised if it was within Sou's calculation too.

"Okay, it's merely a conjecture here, but..." Getting the two to be honest with themselves was perhaps an exercise in futility, but he could try. "For me what he's trying to say was he didn't object. He was only waiting for your approval."

"Huh?"

"Aren't you a little slow on the uptake— hey, stop! I get it, so stop hitting me, people are looking!" He nursed his bruised nose, wondering how threatening one could be armed with just a pair of tablewares.

It snapped her out of it and she reluctantly went back to her seat.

"If I may be so forward, and please don't hit me again, is it so bad if he likes you or you like him?"

She mumbled something he couldn't catch.

Truth was she had asked herself many times. They were certainly good friends, but... sometime, deep down, naming the relationship felt wrong. Not to mention something else she felt from time to time: inadequacy. The Tsukishima girl in the observatory, Annie Kramer, Sally. They had connected with him at an intellectual level she didn't think she could match. She rarely felt self-conscious, but... Whenever those irksome moments flashed in her mind, she would always be awash with unexplainable ire. _Well, sorry for not being a nerd_.

Piecing together what little he could decipher, Loki immediately recalled the conversation he initiated the first time he saw them together, when he so arrogantly thought Sou was too good for her and that place as a whole.

_"You're wrong about my partner. It's true she isn't book smart in the definition you and I are familiar with, but she's quick-witted and resourceful."_

He had no idea how two people who could exchange elaborate concepts like "go to the roof and dispose of those people while I go find the culprit and by the way beware of the one at the stairs" wordlessly (if the stories he heard from his contemporaries were anything to go by) dealt so poorly with what everyone and their grandmothers could see from miles away.

"Well, then!" she glared. "Do you have any hand gesture to signify 'this is all messy and I cannot figure it out yet'?"

After a while, Loki knew he wouldn't get anywhere. At any rate, one might as well solve a Milennium problem before the two made any progress.

As if right on cue, the small bell atop the door chimed. The waiter's cheerful "welcome!" accompanied the door swinging in to admit two new guests. Kana and Loki couldn't guess how far from the earshot they were, but at least part of that sentence was apparently loud enough for their friends to hear.

"Well, what do we have here?" Sou chuckled. "After avoiding a roomful of mathematicians, you guys ended up discussing math anyway?"

"We're just..." Noticing the lack of tension they carried in the morning, Kana asked, "How did the investigation go?"

Sou waved a notebook. She scowled because she was certain it would be filled with inconvenient instructions he expected her to carry out, and she was right. "I hope you're itching to go out, Mizuhara, because the legworks would be yours. By the way, Loki, may I have a bit of your time?"

Eva wondered whether leaving the two alone for the whole day was a good idea after all. as Loki sent Kana a wink on his way out and received a low growl as a reply. Kana studied the notebook with an intensity that deterred Eva from asking, flipping the pages with vengeance. She had no idea since when the nature of her relationship with Sou was anybody's business, because people kept poking their noses in uninvited. The fact that she didn't know why she would be so pissed each and every time and why she couldn't find a simple, satisfying enough answer to wrap it all only added to that frustration.

* * *

Kana didn't know since when she started to pack lunch for two. She convinced herself it was only because he drove her crazy and she would have to do something about it. No room for refusal.

* * *

**2\. Lemma**  
The corridors looked so similar to one another. Kana gritted her teeth, cursing inwardly. How could she find the way to that canteen Eva mentioned? They should have designed the building with better directional pointers. All these ultra-modern aesthetic, all-white floorings and sterile silver walls, wasn't exactly memorable.

"Oh, young lady! You're the one with Sou Touma before, correct?"  
Kana stopped in her tracks, turning around to see an affable face with a fatherly smile.  
"You were one of his professors," she recalled.  
The man nodded. Upon learning where she was heading, he offered to show her the way. Of course she had been walking down the opposite direction for minutes.

She had no idea what subject he taught or how close he was with Sou, but he really did seem like he wanted to know how Sou had been doing. She supplied an anecdote or two, hoping they were sufficient. The professor seemed amused, but he then suddenly sprung a question Kana was not prepared for.

"Is he... is he happy over there?"

He looked embarrassed, perhaps almost apologetic. Kana wasn't sure what to answer, waiting for the professor to explain himself.

"My apologies," he said, sheepish. "You must be wondering why I would ask something like that. Thing is..." he lowered his voice. His eyes turned glassy as he pored into somewhere faraway. "Forgive me, but innocence came so rarely for an old academic like me, it's hard to forget."

Wouldn't hurt to humor him a bit, thought Kana. "What was he like as a student?" she encouraged.

"He was an eager learner," the professor recalled with apparent fondness. "I think a lot of people would treat him differently for his age, but while I won't discount the fact that he's very talented, he's just someone who enjoys what he likes very much."

"It is not a rare trait to my students. After all, the university attracts people of that kind. However, he was also fortunate in the sense that his interest was genuine, not clouded by prospects of careers or such that often plagued his fellow students of older age."

He shrugged. "You see, for some that sows seed of bitterness and may distort the way they perceive the world, ultimately dismissing their academic duties as hurdles to overcome— even though they might have arrived there wide-eyed. He saw this, and learnt. It was both fortunate and unfortunate for him to see the reality of life and human nature so early, and for some reason that kid was both so good and so bad at reading human psyche."

Over the course of the years, traveling with Sou had brought her to meet many academics, but she couldn't for the good of her life figure out why they all seemed so... tormented, for the lack of better words. Simple happiness seemed like a concept too difficult to comprehend for the smartest minds in the planet.

"When I heard he decided to return to Japan for a taste of a normal high school life, as an academic I wouldn't lie; I was disappointed. Those four years would bear fruit if he had chosen to stay with research. One couldn't wait to see what he would produce. Yet in one corner of my heart I was relieved. We keep piling up hopes and expectations on these bright minds— but they too are merely individuals looking for happiness. I'll be damned to say this, but perhaps they don't have to produce anything. They just have to live their lives to the fullest. I've lost many a colleague or dearest students to death and madness contracted in the torturous quest for greatness. I'd like to see him live a fulfilling life."

In the silence that followed, Kana stood mesmerized, though a bit guilty because she didn't know how she would process this little bit of information and whether Sou would appreciate her knowledge of this.

"Ahahaha, I'm getting soft, my colleague would laugh at me. I suppose it's a weird thing to ask, anyway. There, the canteen is right ahead. Don't let me detain you any longer." Perhaps embarrassed at his lengthy monologue, the old professor excused himself afterwards, leaving Kana alone with her thoughts.

Meeting more people from Sou's past life, Kana often wondered whether the life he led in Japan could ever truly compare, whether he missed any of this. He seemed so at home with his books, among people he could talk to, amidst those who could appreciate his talent.

Although free of expectations that had burdened him so, surely life in Tokyo was quaint compared to what he could have?

(In a parallel world, there was a Sou Touma who had never moved to Japan and a Kana Mizuhara who would never know the world outside kendo and classes.

It was surreal.)

* * *

The hallways of Sakisaka High main building were usually deserted a few hours after classes ended, with commotion moving to the smaller club buildings at the opposite end of the school grounds. Yet today, as Kana Mizuhara made her way to the locker room, a considerable number of students were still around, chattering about the newest gossip, life in general, or the upcoming college entrance examination. After a difficult session of career counseling, Kana was only glad for the teacher to move over "Mori, Kikuo". The reason why the school was still packed soon became clear when she reached the outer corridor, with their large windows and uninhibited view to the football field.

She should have guessed when she heard the familiar pitter-patter. She stopped at her classroom, fortunately still open, to get her umbrella out of her backpack. Since it was clear she wasn't be able to jam in some kendo practice, she would like nothing more but the warm confine of her room, preferably within snug swathe of her comforter. As she wrapped her backpack in the waterproof cover, however, she remembered a certain someone who was usually hanging out on the rooftop at these hours. Had he gone home already?

There was no new message in her phone.

"Ah, Mizuhara. Are you here waiting for Touma?"

A classmate of theirs waved from the corner. Kana wasn't sure how her intention was so clearly read, but she wasn't about to ask.

"I am. Have you seen him?"  
"He left for his turn for the career counseling, although if you ask me, I don't get what he's going to talk with the teacher. I mean, he has already graduated college and all..."

Kana quirked her eyebrows. She had somehow forgotten that as a fellow third year student, Touma would be required to attend the same session too. It was almost a foregone conclusion, sometime. Students would mull over their career choices with a teacher. Then what would be there for someone who had had completed his education and perhaps made a career (or two, or three, he was never sure how many kind of job Touma dabbled in) out of it? Must be nice not having to go through this messy process, because having to plan and tell people what you would do when you actually had no idea at all meant one hell of a time.

She should ask him about it, because she was sure curious as hell about that guy's future plans (It was merely a healthy curiosity, of course. They were partners. She would be pissed if he decided he would go somewhere and just vanish someday).

Speak of the devil. The door slid open with a screech.

"Are you done, Touma?"  
"Yes. I believe you're next, Hamamura."

The door slid close again.

Sou noticed Kana right away, immediately striding towards the desk she was at. Kana was just about to ask what he was up to when somebody ran down the corridor and yelled for everyone to hear, "Help! Help! Someone assaulted the teacher!"

Well, they would have to shelve this for later.

She shot him a look he pretended not to see, so she elbowed and dragged him to the teacher's lounge.

...

An hour later, with the matter resolved and the rain finally receding, the duo walked home. The remaining puddles glittered, framing the world in all the color of autumn under the last droplets of the dying sunlight.

Kana slung her bag over her shoulder. "I can't imagine someone would assault the teacher just because she refused to write him a letter of recommendation," she sighed.  
Sou, ever somber, replied as if it was common sense. "That's desperation for you. It draws the ugliness in human hearts."  
Kana rolled her eyes. Coming out of someone else, it would sound like a corny Sunday TV line. "There you go saying those kinda things again."

The usual banter was short-lived because suddenly they have reached the gates bearing "Mizuhara" on the nameplate.

"Thanks for the umbrella."  
"Yeah, yeah. See you tomorrow."

It was only by the time Kana had drowned herself in a heaven made of pillows and blankets following a delightful hot water bath that she realized two things: first, they had shared an umbrella all the way home, and second, she had totally forgotten to ask him what happened in his career counseling.

* * *

The two girls, already in their pyjamas, worked with cheerful hums as they laid out a set of futon. Growing up the only child in the house, Kana had always enjoyed this kind of sleepover, which she tend to associate with the undertones of festivities, like a school trip or a training camp where the night would stretch out for hours and the day wouldn't end until the participants had exhausted all there was to talk about.

"I'm sorry to impose on you, Kana."  
Kana hopped on her own bed, satisfied. Truly, nothing beat your own bed at these hours. She could lie there _forever_.  
"No problem, but really, that brother of yours! You've come all the way here and he just goes out doing god knows what!"  
She really should knock some sense into him next time.  
Yuu chuckled. "That's to be expected of Sou. I don't mind, staying here is fun."  
Kana toyed with her phone then glanced to the window. It was really nice to be indoor in this weather.  
"I wonder if he brings an umbrella... Hey, what's with you?"  
The younger girl was sporting a mischievous grin at Kana, her eyes wide and expectant. "No~thing! It's just... Kana worries about Sou so much, huh?"  
She dropped a pillow.  
"What do you mean about that? It's natural to worry about someone like him. Y'know, sometime he lacks common sense."  
Yuu laughed, still in the same singsong tune. Ah, these two...  
"Alright, alright. So, why don't you tell me the sort of things you got into?"  
Relieved that Yuu seemed content to stop the tease, Kana racked her brain for something Yuu hadn't heard of yet. Sou was bad with telling people what he had done, so Kana was determined to relay Yuu a glimpse of their daily lives, exchanging stories whenever she came to visit. Soon, they were swept into animated discussion, Yuu every bit as enthusiastic as Kana was.

Downstairs, Mrs. Mizuhara made another round to her kitchen, making sure everything was spick and span while wondering how long this new addition to their household would stay. It was fun to pretend she had another daughter to dote on. And such a nice kid she was! With her husband often coming home late into the night, dinner would usually be quiet affairs in the weekdays. She sketched out some tentative meal plans, crossing them as she changed her minds, adding some more as she saw fit. She had to ask Yuu what she liked.

"Hahahaha, that sort of thing happened? Wow, I would love to see his face!"  
"It was the best! All the hours I put into the magic practice was not a waste."  
It was one of the stories Kana was proudest for. Probably that was the one time she could enjoy the purest look of surprise on his face.  
"You know what that means, Kana?"  
Her eyebrows furrowed. "What?"  
"He never suspected you at all."  
Kana shrugged. That certainly was his fall in that particular case. Why he would fail to consider her involvement was beyond her, given he would usually go around naming people suspects with no qualms.  
"He doesn't trust anyone unconditionally. Maybe because he'd been with adults all the time... He's good at his investigation because he never makes it personal."  
Ah, yes. Kana coughed, putting on her best 'Sou Touma impersonation'.  
"He would be 'so and so did this. Wait, why are they angry?'"  
Yuu snorted, and they both grinned.  
"But you, you're different. You managed to fool him."  
"Hey, don't make make a big deal outta it."  
Yuu let out a knowing whistle. Time to change the subject, then.  
"It would be fun having you at home."  
"Huh? Oh, yes." Perhaps Yuu could live with them if she ever decided to continue her studies in Japan, thought Kana. It would definitely be livelier around, and Kana would finally know how it felt like to have a little sister.  
"With the two of you, I'll have a brother and a sister!"  
Wait, Kana didn't mean it _that_ way. She reddened.  
"We... we should invade his house sometime for a sleepover. There must be someplace to sleep between all those books!"  
Yuu, who had been harboring suspicion that they were not talking about _the same thing_, stared at Kana in confusion.  
"Wait, Kana, you haven't heard?"

When Mrs. Mizuhara was decently pleased with her handiworks, the long hand of the clock had shifted one eighty. Her husband would be home anytime now.

Sure enough, the bell chimed.

...

Kana looked blankly at Yuu, who immediately sighed.  
"I should have known, that fool..."  
But before she could ask what it was about, another voice cut into the room.  
"You two seem to be having a good time."  
"Sou! Since when you are here?"  
He was still in his outdoor attire, coat and all, but properly dry.  
"Just now. I was giving my greetings to Mrs. Mizuhara. Inspector Mizuhara told me you're here and kindly let me rode along on the way back."  
Kana would think Yuu would leap to her brother now after waiting for him the whole day, but the girl glared daggers his way instead.  
"Hey, Sou, why haven't you..."  
Sou grabbed Yuu's wrist and led her out towards the staircase.  
"Now, now, why don't we talk somewhere else?"

Kana wondered what that was about and why it upset Yuu so much.

* * *

The weather prevented them from going out as planned and while Kana was bored out of her mind, Sou didn't object to having more time to work with this project a friend sent him. Leaving her with nothing to do and no one to talk to was a recipe for disaster, so soon enough she began poking on random things to amuse herself.

"Hey," she peered from his shoulders, plopping on a seat beside his and leaning to the back of his chair. "What are you looking at? Whoa, they look like cherry blossoms!"

Sou adjusted the inclination of his monitor so Kana could see more clearly. "It's called fractals," he explained. "You can use mathematical formulas to generate these infinitely repeating patterns."

She hummed. "So you mathhead does know a thing or two about beauty."

"If you say so..."

"Say," she put a finger to her lips, trying to remember. "Didn't that Ru...Russo... something said something about this? Math being truth and beauty or something."

Sou looked at her like she had sprouted a second head. "Since when are you reading Bertrand Russell?"

She ran her hand through her hair. "Well, Loki told me." It had been mentioned in one of their talks, though she had forgotten the context. Loki was a talkative person, so they would end up striking all sorts of conversation whenever they were stuck together. Most often the conversations would lead back to Sou, however, but he didn't need to know.

Sou narrowed his eyes, resting his head to one arm on the desk. "Why does it seem like you retain what Loki says better than you usually do mine?" Kana could swear it was a pout. But Sou Touma didn't pout.

Kana shrugged. "I can't help it, his explanation is usually easier!"

Sou grumbled. Maybe he really should work on that, because for all his experience tutoring, he always lost on this aspect.  
Kana stuck her tongue out.

"Russel said math being a beauty, of the cold and austere type," he sighed. He knew defeat at the door.

"Do you agree?"

"I don't see it that way, at least not anymore. I consider math not only as a pursuit of truth but also the art of communicating, a way to transcend the language barrier to convey your meaning."

"See, you've always got to make it difficult."

"Alright... I get it."

Kana glanced at the screen again. "But it's beautiful nonetheless. I know! Let's see the cherry blossoms together again in spring. What do you think?"

"Sure. I'm looking forward to that." Kana saw him smiling, however slightly, and she was satisfied. The next few hours was spent watching him clicking, typing, and dragging various things on the screen, and her patience was rewarded with Sou showing her various other patterns he could generate. Snowflakes, crystalline flowers, trees, flames, butterflies. When she asked him to mimic the patterns on her lunchbox _furoshiki_, he called it quits. She didn't even realize when the rain let out.

When Kana reached home later that evening, her mother called from the kitchen to inform her a letter had arrived. She wondered who it could be from, as her friends would usually send emails to her phone instead of a formal snail mail.

When she picked it up atop the stack of bills and reports addressed to her father, she found the name 'Nashida' written on the envelope in a terse, clean handwriting.

* * *

Propagated through the grapevines and spoken in hushed tones only under absolute secrecy, the students started to place bets about the two.

* * *

**3\. Conjecture**  
Who would be in the mood for parfait when it's so cold outside? Apparently an esteemed Japanese intelligence officer, known to his contemporaries as Nashida, was one. Kana eyed the tempting extravagance in front of her, as well as the man who casually wolfed down the entire monstrosity like it was the most natural thing in the world.

Navigating over the customary 'thank you for coming's and other small trifles, Kana rejected his offer for similar order and asked for a cup of hot caramel latte instead. The rainfall didn't seem like it would cease anytime soon, trickling down the shop's frosted glass windows in ways almost artistic. He had called her with an old-fashioned letterform in this day and age, so she expected something big to drop any time now.

Formality set aside, Nashida finally made his move once the waiter came with Kana's order.  
"I won't mince words. Do you know whether or not Sou Touma will return to America?"

The severity of those words struck Kana, who was busy planning what to shop for dinner tonight as she stirred her drink absentmindedly. As such, the most intelligent response she could utter was a, "Huh?"

Nashida sighed. "You do know that he possesses dual citizenship, yes? Once he turns 20, which would be in a few years now, he would have to choose whether to retain his Japanese or American nationality."

Ah, Touma's birthday was closing in. It was almost surreal for her to consider it was time for them to make big changes to their lives, because the three years of their high school seemed like it would stretch forever. Perhaps she should think about it sooner, with the career counseling and all.

What would Touma choose?  
Problem was she did not know.

Nashida, however, was not satisfied with such an answer.  
"The government wants him to stay in Japan. I'm sure you would understand."

He shifted, wielding the spoon as if it was his tool for diplomatic negotiations.

"Brain drain is a serious problem and Japan has been losing to Europe and America for a long time because despite claiming to favor the development of science and tech, young STEM graduates are not so appreciated here, with its antiquated bureaucracy. Rather than waiting two, three decades to finally get your own lab, young scientists often propose their idea oversea and have them realized right away."

Now, Kana would have taken the conversation really seriously had Nashida not been chewing a very bright piece of cherry as he waited for her reaction.  
She wondered what Touma would say about this, wondered what he would choose because now that question burnt deep in her mind and she was eager to know. Irritatingly eager. Would he leave? It would be very weird without him around. True, he told her before that countries like Swiss would pay a lot for mathematicians. Didn't he ask Loki the other day about a research opportunity in his lab? Wait, was she worried? What was she worrying about?

Not getting the reaction he wanted, Nashida plodded on.  
"CIA has his friends and mentors under close surveillance. I have no doubt they want him too. He's laying low, but his achievements haven't gone unnoticed."

So he was saying the best institutes in the world were fighting for that eccentric guy. World sure was strange.

But Kana was not prepared when Nashida zeroed in the reason he called her.  
"Wait, what? You want *me* to change his mind?"  
"Only if he decides to return to America, that is."  
"You want me to convince him to stay?" she repeated.  
"If you can, that will help us a lot."  
Nashida obviously didn't realize how offensive this sounded, because he continued.  
"Think about it. You'll be doing a service for Japan."

That's it. Her eyebrows twitched.  
"Screw it, I'm not going to be one of your pawns!"  
Simmering anger made itself known as she threw loads of expletives his way. How dare he! She would drag Touma to hell and back with all her might if she felt compelled to do so, but doing so for the benefit of a bunch of old men in crazy political circuits? Never.

Kana made sure to order the most expensive item in the menu before she stormed out the door, because he had offered a treat anyway and she was so pissed but decided that picking a fight with a government officer was *probably* not the wisest course of action. But boy, was she pissed. Plus, all his shortcomings aside, this guy Nashida did know the best dessert parlors in town.

The man she left behind sighed in exasperation. That proved to be more difficult than he thought.  
"I'm sorry, can I have another one of your Sky Tree King Parfait?"  
Alas, at least he could dig in before he had to present his report to the top brass.

* * *

"Hey, Touma."  
Touma looked up from the manuscript he was examining, a thick bound of yellowed paper attached to a set of black and white photographs. Laying on his desk was what looked suspiciously like a fading star map. Scraps of notepads scattered below the folds, filled with messy scrawls. He had been preoccupied with this small project ever since they visited a college open house in Friday.

"Yeah?"

"I didn't manage to ask you all week, but what did you say on your career counseling?"

"What did you say in yours?"

"Ah. I got tired of the teacher badgering me, so I told her I'll try for JSDF."

"The JSDF will be a fool for not taking you in."

"Why does that sound like an insult?" she complained. "Anyway, quit dodging the question."

"Oh, that?" He resumed reading. "Nothing much. The teacher relayed me messages from some research institutes." It was less a career counseling and more a nationalist propaganda, come to think about it. The teacher hadn't met a case quite like his before, so all they did were delivering offers they fielded for him. At first, he was surprised because he had no idea that people had been sending the school advances. Ultimately, he was glad that the faculty did honor his wish for a normal school life and waited until the end to tell him about it.

She whistled. "So that guy's telling the truth. People want you."

"Huh? Who are you talking about..." She held out the invitation sent to her house. "Oh, you met Nashida."

She nodded. "I did. I doubt you aren't getting similar requests from American research institutes."

There was no use hiding it if the government had been playing dirty, then. Approaching people he was close to? He should have his intention clear before any of this should happen.

"Well, yes," he sighed. "There has been a few."

"So have you decided, then? What you're going to do after high school?"  
Sou looked straight at her, choosing his words carefully because there would be no doubling back and it wasn't how he intended to tell her, but what was done was done and she wouldn't possibly let him off the hook again. Moreover, time was running out.

"I have. I told the teacher I'm going to return to America upon graduation."

He inspected the damage. Kana was stunned, though not particularly surprised (or she had been more skilled in concealing such reaction). He wondered how much Nashida had been telling her, and how much she had anticipated this outcome.

"I've made up my mind," he added, rather hastily, though it sounded more convincing when he rehearsed it over and over in his head. For some reason saying it to her face was more difficult that he'd assumed. "I'm going to return to the States and live with Yuu while I complete my Master's. In my attempt to dispel the shadows, I had unwittingly doomed Yuu into the same loneliness I once had. There's still two more years until she finishes her schooling. I intend to make it up for her."

There was still a few other things he intended to explain, but he never got it through before a blow struck him.  
"Hey, what was that for?!"

"For taking this long to tell me, dummy! You've got this planned an awful long time, right?"

He deserved that, perhaps.

"Are we still going to see the cherry blossoms in spring?"

He found it particularly astonishing she had to ask. "Of course. I will still be here until a few months after graduation."

She sighed, "You really could have told me sooner. If I didn't ask, are you going to just disappear?"

If there was one thing that infuriated Kana to no end, it was Sou's habit to leave off problems once he figured out the answer. Somehow, it never occurred to him that other people might want to hear the answer too. That was how he got tangled in misunderstandings. His avoidance of Loki, his silence about Yuu's dog, the truth behind the Annie Kramer case, his decision this time. No. He skipped the explanation and cut straight to bloody proceed alone. While she entertained the possibility from time to time again, the reality never set until he spoke of such a definite plan.

"I apologize. I had intended to inform you, but the timing never felt right. And no, for the record, I have no intention of not telling you at all."

She would have hit him for the sheer nerve of smiling that way, but it looked so sincere she failed her earlier resolve to be annoyed. Why should he make every single thing difficult?

Meanwhile, in the back of his mind, Sou saw how events would transpire if he neglected to tell. Deprived of justification, rather than sulking, she would probably rage and, if she so wished, chase him to the end of the world to give him a piece of her mind. Somehow that amused him.

"I'm glad you'll finally be there for Yuu," she said, "though it'll be different without you around."

"So that's why, Mizuhara. Would you come with me?"

"Eh?"

"I've enjoyed my time in Japan thanks to you. It's never boring around here. So, would you come with me? To America?"

* * *

Noriko Kishikawa waited until her friend got everything off her chest, because cutting Mizuhara Kana's stream of thought midway through would usually yield poor result. The girl was so headstrong it would be better to let her rant, though piecing things when she got incoherent and barely making sense was a feat in itself.

"So," said Noriko after Kana had finally stopped for a full minute, "what did you say?"  
Kana plopped down, laying on her back against the cool rooftop tiles so she could have a full view of the sky.

"I don't know. I haven't really thought about..." she made some indecipherable hand motions as if she was swatting an unseen fly, "all this, you know. I don't really think about what is on ahead, the future seems like it's so far away."  
Noriko glanced to the ladder leading up to the uppermost part of the roof where the subject of their talk usually spent their time. For reasons unknown he was not there today.

Kana heaved. "Ahhhh! That guy, he just has to do that out of the blue!"  
Noriko picked a slice of cucumber from her packed lunch. Only ten more minutes until the bell rang for the next lesson. "I'm actually a bit envious, you know... That's such a bold proposal."

Kana wasn't really listening, a habit Noriko was used to.

"My father would give me an earful, I'm sure," replied Kana, who was glaring daggers to the direction Noriko glanced at earlier. How dare he put her in such turmoil and just disappeared for the day!

Noriko wondered whether they could wrap this up before lunchtime was over. She didn't really know what to say to Kana, who obviously needed time with herself.

"Maybe you can just tell him you're going with your boyfriend..." Kana glared, she winced. "...or something. I'm sorry, I was just kidding!"

"...Noriko, I don't even know what I'm going to do if I go..."  
Could she even make it to an American college? Or would she take up a part-time job somewhere and mind the home with Yuu? Or what? She had been in many foreign countries, but never _to stay_. She could barely speak English despite the siblings' tutelage.

"How is it any different from usual, anyway? You have spent so much time with him going all over places. It's a fact, don't look at me like that. It could work, you know. You going wherever he goes, solving cases together... or something. That's how it always goes, anyway. He doesn't seem to mind."

Kana bolted upright. This time Noriko saw that for once her friend was being more serious than she previously thought. Kana spoke slowly, choosing and tasting each of her words like she wasn't quite sure how to put them together. "...Maybe you're right," she began, "but I don't think I want to pin my dream on someone, even if he doesn't mind. It feels wrong. I mean, this is my life, right? I should be the one taking charge of my own choices."

Noriko widened her eyes.  
"Huh. That's deep coming from you."

Kana wished she could find an answer somewhere in the clouds. It would be nice to drift off just anywhere, without having to ponder on things like this. Life seemed much simpler when they were sixteen.

* * *

Inspector Mizuhara's reaction when he heard the news from her daughter over dinner was admittedly not at all like Kana thought it would be. Instead of a bold refusal or protective comments, he instead scratched his beard and scrunched his eyebrows in ways that hinted at some confusion, but most definitely was not anger.

"America, huh? That's really quite far, but if you take care of yourself and make it home every now and then we should be fine."

Kana wasn't sure what to take of this. _What?_  
She set the bowls and chopsticks aside in a clatter.

"Dad? You're— you really have no problem with me to just pack my suitcase and— move over to America? Just like that?"

"Well, sure, if that's what you want? It's gonna be quieter around here, though..." He reached out for a bowl and a pair of chopsticks, then proceeded to help himself some rice since it was clear his daughter was too busy being surprised to remember her table duty.

She was sure her mouth was agape. "No! I mean, that sounds like you don't want me home anymore. I mean, geez, can you be more worried about your daughter or something?"

Inspector Mizuhara lowered his eating utensils and let out an audible sigh. He looked straight into his daughter's eyes, and tried to employ the most patient tone he could.

"Kana," he started, to which Kana flinched a bit because perhaps she went too far and flipped the switch. Damn. "One time I came home to hear from your mother you've gone _to Malta_. Before that, Greece. America. Egypt. France. Italy? Probably somewhere else I've lost count by now."

Kana actually had the decency to blush at that. She bit her lower lip, her fingers tapping the dining table nervously. Okay. Maybe her father had a point there. Her passport did seem _a bit_ more colorful after high school, and she might have ran out of pages recently, but she didn't go out that much... was she. Actually, she _might_ be out of Japan next week too. She couldn't help it. That guy had the weirdest friends bringing the most interesting cases. It definitely wasn't her fault.

As Kana tried and failed forming a comeback, Inspector Mizuhara, apparently satisfied, exchanged meaningful glances with his wife.  
"So yes. Don't mistake me, I have my reservations and I am worried from time to time, but I realize you're an adult now and rather than placing restrictions for you to break, I'll just believe in you. I trust you to make important decisions for yourself."

The speech stunned Kana, touching her in ways she didn't expect. While it was true that Inspector Mizuhara had stopped berating her for appearing in a crime scene, even asking her what she thought about a particular case once or twice (somehow figuring out she had heard about it one way or another), and welcoming her from her international trips with less and less grumbling (he'd even resorted to asking for souvenirs in jest for the most recent one), she never thought her parents would have put that much consideration into her whimsy.

"I admit weekend jaunts is not comparable to actually moving out, but we've known for some time that you will leave home sooner or later. It's not easy to come into terms with, believe me, but we have talked it over and over again. Just... keep in contact."

Kana hissed. A particular line her father uttered before now became prominent in her mind as she grasped what he just said. He expected her to escape if he made prohibitions. She pouted, hunching down to rest her chin on the table.  
"Do I really look like I will sneak out in the middle of the night?"

Her father stared at her for a full ten seconds and Kana had to concede. She would. She totally would.

"But really," said Mrs. Mizuhara, who had been observing her family's conversation with quiet interest for some time now, "for a guy to take away our Kana this quickly..." She shook her head, smiling.

Her husband played along, smirking. "Ah, yeah. I really should have paid more attention the first time I saw his shoes on the porch."

Kana choked on her miso soup, sputtering out incoherent protests before managing, "Dad! Mom! You're giving him too much credit. I'm pretty sure the blockhead doesn't even understand the implication of his offer." Why would everyone just _assume_?

Her mother chuckled. For an only daughter, she sure was lively enough for their days. It was predictable, but she couldn't help but feel a bit sad her girl would be leaving nest so soon. "But you haven't made your choice yet, right?"

Kana sighed. "Yeah..."  
Although the conversation she had earlier with Noriko helped, she hadn't come closer to figuring out what she really wanted to do for herself.

"Well, as we've established tonight, your father and I would support whatever you decide to do, so just take your time and live freely," said Mrs. Mizuhara, adding a glop of spinach to her husband's bowl, ignoring his scowl.

"What will you do if you stay in Japan?" Inspector Mizuhara had decided that the difficult part of the conversation had come to pass, so he took out a stack of documents and reading materials from his briefcase as he munched on his meals. Mrs. Mizuhara glowered and gave a warning tap to his shoulder. She had always been against working at the dining table.

"That... is what I've been thinking about. Is that the police department newsletter?"

Kana recognized the layout. Her father brought these publications home from time to time, and sometime Kana would read them, but this time something else came to her mind. Her father looked up from his notes.

"Hm? Ah. Sasazuka told me there's something in here I might find interesting."

Kana took the magazine, giving it tentative looks. Could she have a future in law enforcement? And a teacher mentioned communication for her once, citing her sociability. She had always enjoyed the data gathering she did for Touma, after all.

Man, she really ought to have thought of this sooner.

But for now, dinner was waiting to be devoured. All the talks made her hungry.

(Soon, she was busy chomping down everything and Inspector Mizuhara inwardly laughed. His daughter ate enough for three.)

* * *

Ever since they saw the cherry blossom together for the first time, Sou was sure of one thing: Kana was truly a child of spring. She was the embodiment of everything he'd known spring was harkened to: renewal, indomitable spirit, evergreen vivaciousness, infectious ebullience, and beneath all gentle resilience. Through three years of high school, the flower viewing season was among things he looked forward to each and every time.

This year, the season was doubly special for a lot of reasons. He sat on his usual vantage point on the rooftop, watching as rows and rows of student flooded out from the main building. A sea of blue contrasting petals of cherry blossom swaying in the wind, a colorful end to his colorful days in this place. The ceremony had ended a while ago, but he stayed behind to wait for someone he knew would be there once she finished saying goodbyes to everyone in their year.

_panta rhei._ Everything flows. Very soon a new batch of fifteen and sixteen year olds would take over their place, sitting where they used to sit, enjoying lunch where they used to eat, participating in club activities where they used to spend time in. Spring was a season of change, and it was exactly this ephemeral quality that formed its distinct beauty.

He had tried mingling with people, but it had been three years so he allowed himself this day to retract a bit. He could always count on a certain someone to keep him not too far away, anyway, and sure enough, he heard the familiar clang of the rooftop door unlatching, soon followed by a familiar set of shoes rushing towards the steel ladder, and the whole sequence was finished with a rolled diploma hitting him in the face.

"You aren't supposed to hole yourself up here on graduation day!"

He saw that coming and that still hurt. Kana huffed, and for a second he thought she would stomp at his feet until she sat down and scooted closer.

"Have you met everybody?" he asked.  
"Uh, huh. I took some photos, met Noriko, Umemiya, Kosaka, and some others, but I figured that should be enough. I mean, there's still the farewell party and all ahead. I'll just take a break for now."  
"All by yourself up here?"  
"Huh. I'm a hundred percent sure a loner would be here with his books, graduation day or not."  
She laughed.

Kana had told her parents to return without her, promising she would bring him home before supper. She was halfway trying to convince Sou to give "the graduation cheer" a chance, taking part in the endless fistbumps and congrats and goodbyes, when a deafening grand procession of trumpets and drums roared in the air, beating all the other noises by a wide margin. Dumbfounded, the two looked down only to find a giant poster of Himeko Enari had been unfolded from the western wing of the main building. There were explosion of confetti, thick white smoke that looked suspiciously like dry ice, and a group of three proclaiming their dedication to their "Queen" with a megaphone. (Or so it seemed. It was really hard to hear anything over the circus, but they could hear the word "Queen" loud and clear.)

"Isn't that... against the rules?"  
"Of course," replied Sou. "So are you sure you want to go down there and be involved in... whatever that is?"  
"Y'know, on second thought staying up here sounds like a good idea."

They laid down, basking in momentary peace. Above them, birds glided through the clouds. The flowers were in full bloom. Minutes passed until the noise from the grounds subsided. The faculty had probably dealt with the stupid trio, the third years were probably heading out to the farewell party or going home with friends and families.

"So," started Kana, a bit anxious. "About your offer..."  
"Have you given it some thought?"  
She nodded, then gulped. "After thinking about it... I'm sorry because I have to turn it down."  
Sou's face didn't betray his feelings. His face was bereft of any discernible expression. Kana couldn't read whether he was disappointed or not. "May I know why?"  
"I still have a lot to figure out, but when I spend my time looking around, I realize I really like it here, and I want to see what I can do for myself in the future. I don't think I can do it if I depend on someone else."  
Needless to say, it was extremely tempting.  
She grinned. "So maybe not now, but really, thanks for the offer."

Kana wondered whether she might regret her decision, because it would be going to be awful different without this eccentric guy around her. She had gotten used to him being a permanent fixture in her days she had forgotten how it used to be before.  
He should at least try to keep in touch, or she would be so mad.

He smiled softly. "Yuu's going to be disappointed."  
"Yeah. I would tell her I'm sorry too." She glanced at him, smirking. "Well, how about you? Are you disappointed?"

He still donned his trademark know-it-all face which never failed to incense her. It was unfair for him to read her like a book but she couldn't do it the other way around.

"What?"

"Patience." He reached into his coat pocket. Kana heard a jingling sound and she was presented with a set of keys.  
"Here, I'd like you to have these, Mizuhara."

She reached out for the keys, dangling from a weirdly shaped charm with a small circle at the middle. Roman S? L?

"My keys. I couldn't possibly have my books shipped all the way here again, so... until I return, would you mind watching over them? I no longer have access to amenities like the swimming pool or the gym, but feel free to help yourself if there's anything you need from the house."

She had no idea how she looked like in the mirror, but her guess was ridiculous. Perhaps eyes wide open, round as a pair of saucers. "Wait, return? You're going to return to Japan?"

His eyebrows furrowed. "Well, yes. Graduate studies would just take about two years, then I'll be back," he tilted his head. "Unless... you... don't want me to?"

He shot her a questioning look. She shook her head. "No! That's not what I meant!" She laced her fingers, fidgeting. "I just thought... nationalities... chances..."

"Wait. Whoever gave you the idea?" Then it hit him. "You overheard my talk with Loki. I should have known," he sighed.

Kana scowled. "In my defense, you were really suspicious."

"I just asked him to run me through some professor I was interested to study under, okay? And getting him to look over my application."

Kana was still indignant, you-should-have-told-me-sooner written all over her face. She softened after a while. "There are better opportunities overseas for mathematicians like you, right? You said so before."

"Opportunities are made. Nowadays you can practically work anything from anywhere."

They locked eyes with each other and she could see just as she had made her choice, he too had made his.

"...the trips you made without telling me?"

"I went to the civil registry to find out what paperworks I need to fill to claim citizenship."

Finally coming to terms with the fact that he wouldn't just leave, Kana felt a heavy weight had lifted off her chest. They really should try to be more honest, she thought. Then something else struck her. She looked at the keys on her palm.

"Hold on. If you've prepared this, then... you've guessed what my answer would be in the first place, right?"

Sou said nothing. After all, being part of this world was an important piece of Kana. She showed him how it meant to live and connect with people, so it was impossible for him to take her away without taking what made her special. She was headstrong and self-sufficient, she wouldn't just accept a life given by someone else.

"So when are you going?"  
"I enrolled for the autumn term, so... probably the end of summer."  
Two seasons away, she thought. She was not sure how plentiful two seasons would be. She used to be certain he would be there on the school rooftop come morning.

"Promise me you're going to return, alright?"  
"I will."  
"Beside," she added with mirth, "Don't you think you can get away so easily. You better start attending to that phone of yours!"  
He chuckled. "I'll be looking forward for that."

They stayed there until it was almost dark and the first blush of the moon loomed in the horizon (a particularly beautiful one tonight, he thought). The school guard, annoyed but willing to give them one last pass, ushered them out once the sun had completely set.

Sou watched Kana's scarf billowing in the breeze as she skipped round the riverbanks, grinning when she took one stride too far and fell flat to her face. She threw him mudcakes, deaf to his protests. Around them, people gathered to amuse themselves with the scene of two diploma-toting highschoolers running around like two children in the playground. There was so much they had yet to figure out, but she was willing to take things one step at a time.

The winter had ended, the snow melted.

* * *

Loki wondered who was stupid enough to incite Sou's wrath, because having him as an enemy was among the worst nightmare one could ask for. Especially because he knew what (or rather, who) the matter pertained to. Nobody was going to die tonight, but somebody would certainly have their life ruined.

* * *

**4\. Proposition**  
The first few messages, they forgot that they were countries apart and wouldn't be able to run for lunch whenever they felt like it. In the coming days, though, it was apparent that something was missing (though nothing was ever said out loud). In certain moments, where distance seemed unbearable, both of them were glad of the myriad excuses they had for meeting: Yuu's birthday, holidays, Alan and Elie's requests, cases (tons of them, she did not disappoint), or just the plain old, "I thought I'd drop by for the weekend." Not even Inspector Mizuhara was surprised to see him joining in dinners or spring cleanings like he never left at all, though he had acquired savviness to not point the fact.

Phone calls couldn't replace actual face-to-face conversations, but they were close substitute.  
"So, what's this charm about?"  
"Charm?"  
"You know, this S-shaped thing on your keys."  
"Oh. It's a closed loop."  
"Closed loop?"  
"In surface integral, no matter which path you take, whether the straightforward line or one full of unexpected twists and turns, the amount of energy involved in the displacement is the same."  
"Huh. Don't you have a nicer explanation?"  
"Well... then you can say the closed loop also represents something else."  
"That is?"  
"No matter what, every path leads you back home."

* * *

Fate seemed to unfold in the strangest ways. In one of their vacation-slash-case solving, a jet-lagged Kana found herself across one Elie Brad on the breakfast table, and unloaded upon her her worries and uncertainties about her future career. Elie blinked several times, then proceeded to faze the younger girl with a nonchalant statement.

"Really? If a job is all you need, I'm sure I can find something for you in Elie and Alan Foundation."  
Kana gawked.  
"I've known you for a while, so I think a nonprofit organization would suit you. I need someone with keen eyes to help us identify people in need, address their problems appropriately, and advise us where to go from there. If you're interested, just call me."

Alan might have given up his quest to recruit Sou Touma, more-or-less kind of sort of, in honor of his promise way back, but no one stood in the way of Elie vying for this girl. Bright, persistent, and fiercely loyal, Elie knew a potential human resource when she saw one.

Beside, she could even help Elie rein in Alan every now and then, and having an almost direct access to the coveted Sou Touma's brain would simply be the icing on the cake.

* * *

"Are you free on Golden Week? My family insisted that you have dinner with us."

She had to stifle a laugh hearing how dreary he sounded like, wondering how much he had been hounded to finally put the request through.

"Dinner? Then why ask me for a whole weekend?"

"Come on, the thing with my parents... the dinner might end up being lunch two days and half a globe away." She imagined him rolling his eyes. If he wouldn't stop sighing, people would mistake him for being 81 instead of 18.

He told them to stay put, but he did not keep his hopes high. The Touma parents did not have good track record in staying put. Meanwhile, Kana thought he was being a big baby and it wouldn't be so bad. She put a word for her parents and circled the holiday on his calendar, looking forward to tell Yuu all about college.

However, sure enough, a week later Kana found herself fishing in Nome at the end of a grand chase comprising of seven towns in five different countries.

At least said dinner went well, albeit a bit too awkward and embarrassing to her taste at some point (Yuu put _a little too much_ words about her to her parents, apparently). Once they were over with the misunderstandings, Sou's parents were just too glad to tell her stories after stories about his childhood she gleefully listened to (the person in question denied to comment).

At the end of the day, they strolled the coast which seemed to stretch on forever, where wisp of aurora borealis descended to dance and flicker and whirl like the something out of a witch's cauldron against the star-speckled sky. She wondered what lay beyond for tomorrow, for her, for him, for them. She looked back. There was a twinkle in his eyes, and he was smiling.

(If infinity was tangible, that was how it felt.)

* * *

She was not sure what to blame— Her alarm clock for being so damn squishy, or her landlord for forgetting to wake her up on time. Either way, as she rushed through the packed arrival corridor of Narita International Airport, she was a bundle of crankiness and anger.

A sudden screech followed with two minutes of confusion certainly was not helping. People yelled at each other, and now even the officials were shouting something intelligible. Why should they be so loud? Why was the place so large, and what was happening?

Her stride was stopped by an officer in uniform.  
"No entrance past this point, Miss. A robbery just took place, and the culprit must still be around. We cannot let anyone pass until they're thoroughly searched. Would you please follow me to the office?"

Kana Mizuhara was not amused. At all.  
"Are you kidding me? I absolutely have to meet someone! His flight could have landed anytime now!"

"Pardon me, Miss, but we can't-"

Before Kana could form a reply, slowly, the crowd parted, revealing a smug grin and a familiar voice.

"I'm sorry for my intrusion, Sir, but if I may be so bold, would you care for an assistance for this case?"

"Huh? Who are you?"

"Just a traveler wishing to return home soon. I'm afraid you're detaining my companion."

And she laughed, truly laughed, because the case might as well be closed right then and there.

_-Q. E. D-_

"How did you know I was there?"  
"It was just like you to be in the center of a commotion. I figured out I better interfere before you mauled the security officer or somethi... Ouch!"  
"Say that again!"

Some people, upon a chance meeting for the first time, would inevitably spend their whole lives together. They had forgotten how days were before that and a future devoid of that person, while possible, was unthinkable.

_-Thus Ends My Demonstration-_

* * *

**.**

**...**

**.**

* * *

**Footnote**  
[1] Georg Cantor was an American mathematician renowned for, among many other things, his works on transfinite numbers.  
[2] Morris Kline was a pure math researcher until he took interest in applied cases, and later dedicated a large portion of his works to communicate math for nonmathematicians and provide commentary on math educations. This fanfiction was partly inspired by "Pea Soup, Tripe, and Mathematics", "Why Johnny Can't Add", and "A Critique of Undergraduate Education", including the section about Richard Courant, and the passage was excerpted from "Why Johnny Can't Add" (Kline, 1973).  
[3] JSDF stands for Japan Self-Defense Forces, the national military unit.  
[4] Bertrand Russell was a Nobel Laureate philosopher and mathematician, probably the most well-known figure in this fanfiction as his multitude of essays covered a lot of topics outside math. The quote was taken from "A History of Western Philosophy" (Russel, 1945).  
[5] America doesn't really mind dual citizenship. Japan, on the other hand, is strict about this.  
[6] The first sentence in the first and last paragraph was paraphrased from QED iff, v1c1 (Katou, 2015).

**Author's Note**  
What's my take on the two years interim?  
Honestly the two of them are so independent they would be able to handle separation easily and amicably. Besides, the Toumas probably have enough mileage to just take a transatlantic flight whenever.  
Also everyone's eating all the time. I'm sorry. Let's see how much easter eggs you guys could find because I lost count.

Got this written since Irregular's release of QED v49 in July, each time adding rambling annotations but little narrative progress. Still not sure whether I read a couple books and half a dozen math papers as an excuse to write a fanfiction (with unnecessary footnotes!) or the other way around (that I do realize is gratuitous yet reflective to how I derive my enjoyment from QED). The divide between pure and applied mathematicians may have been exaggerated. They usually could go along well enough... if not left together for too long. After much deliberation, I decided to release rather than consign this to the depths of my draft folders, though I remain unsatisfied with the result.


End file.
